Author:
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Vispa, Alessandro; Romanini, Michela; Ramos, M. A.; Pardo Soto, Luis Carlos; Bermejo, F. J.; Hassaine, M.; Krivchikov, Alexander; Taylor, Jonathan; Tamarit Mur, José Luis
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Abstract:
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We present a dynamic and thermodynamic study of the orientational glass former Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane, CCl
2 F-CClF 2) in order to analyze its kinetic and thermodynamic
fragilities. Freon 113 displays internal molecular degrees of freedom that promote a complex energy landscape. Experimental specific heat and its microscopic origin, the vibrational density of states from
inelastic neutron scattering, together with the orientational dynamics obtained by means of dielectric spectroscopy have revealed the highest fragility value, both thermodynamic and kinetic, found for this
orientational glass former. The excess in both Debye-reduced specific heat and density of states (boson peak) evidences the existence of glassy low-energy excitations. We demonstrate that early proposed
correlations between the boson peak and the Debye specific heat value are elusive as revealed by the clear counterexample of the studied case. |